Oxide semicondutor thin film transistor

ABSTRACT

The present invention relates to a thin film transistor, a thin film transistor array panel, and a manufacturing method thereof. A thin film transistor according to an exemplary embodiments of the present invention includes: a gate electrode; a gate insulating layer positioned on or under the gate electrode; a channel region overlapping the gate electrode, the gate insulating layer interposed between the channel region and the gate electrode; and a source region and a drain region, facing each other with respect to the channel region, positioned in the same layer as the channel region, and connected to the channel region, wherein the channel region, the source region, and the drain region include an oxide semiconductor, and wherein a carrier concentration of the source region and the drain region is larger than a carrier concentration of the channel region.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2012-0059605, filed on Jun. 4, 2012, which is herebyincorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a thin film transistor, a thin filmtransistor array panel, and a manufacturing method thereof.

2. Description of the Related Art

A thin film transistor (TFT) has been used in various electronic devicessuch as a flat panel display. For example, a thin film transistor hasbeen used as a switching element or a driving element for a flat paneldisplay such as a liquid crystal display (LCD), an organic lightemitting diode (OLED) display, and an electrophoretic display.

Typically, a thin film transistor includes a gate electrode connected toa gate line transmitting a scanning signal, a source electrode connectedto a data line transmitting a signal applied to a pixel electrode, adrain electrode facing the source electrode, and a semiconductorelectrically connected to the source electrode and the drain electrode.

For higher TFT performance, fabricating transistor from thin film of asemiconductor is an important factor in determining characteristics ofthe thin film transistor. The semiconductor typically includes silicon(Si). The silicon can be divided into amorphous silicon and polysiliconaccording to a crystallization type, wherein the amorphous silicon has asimple manufacturing process, but has low charge mobility such thatthere is a limit in manufacturing a high performance thin filmtransistor using the amorphous silicon, while the polysilicon has highcharge mobility, but additional, complicated processes of crystallizingthe polysilicon may be required, thereby increasing the manufacturingtime and cost.

To compensate weakness and benefit for the amorphous silicon and thepolysilicon, various approaches have been tried for making a thin filmtransistor using an oxide semiconductor having higher electron mobilitythan the amorphous silicon, a high on/off ratio, and high uniformity,but a lower cost than the polysilicon.

However, if parasitic capacitance is generated between the gateelectrode and the source electrode or the drain electrode of the thinfilm transistor, a characteristic of the thin film transistor as theswitching element may be deteriorated despite the above variousapproaches.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the invention andtherefore it may contain information that does not form the prior artthat is already known in this country to a person of ordinary skill inthe art.

SUMMARY OF THE INVENTION

The present invention relates to improving a characteristic of a thinfilm transistor including an oxide semiconductor. Also, the presentinvention relates to reducing a kickback voltage caused by a parasiticcapacitance in a thin film transistor array panel including a thin filmtransistor and a signal delay.

Exemplary embodiments of the present invention provide a thin filmtransistor. The thin film transistor includes a gate electrode. Thetransistor also includes a gate insulating layer positioned on or underthe gate electrode. The transistor includes a channel region overlappingthe gate electrode, the gate insulating layer interposed between thechannel region and the gate electrode. The transistor includes a sourceregion and a drain region, facing each other with respect to the channelregion, disposed in the same layer as the channel region, and connectedto the channel region, wherein the channel region, the source region,and the drain region comprise an oxide semiconductor, and wherein acarrier concentration of the source region and the drain region islarger than a carrier concentration of the channel region.

Exemplary embodiments of the present invention provide a method ofmanufacturing a thin film transistor array panel. The method includesforming a gate electrode on an insulation substrate. The method alsoincludes depositing a gate insulating layer on the gate electrode. Themethod includes forming a semiconductor pattern on the gate insulatinglayer. The method includes forming an etch stopper intersecting andoverlapping the semiconductor pattern on the semiconductor pattern. Themethod includes treating an exposed portion of the semiconductorpattern, thereby forming a source region and a drain region in theexposed portion of the semiconductor pattern, wherein a carrierconcentration of the source region and the drain region is larger than acarrier concentration of the channel region, the channel region being aportion of the semiconductor pattern covered by the etch stopper.

Exemplary embodiments of the present invention provide a method ofmanufacturing a thin film transistor array panel. The method includesforming a semiconductor pattern comprising an oxide semiconductor on aninsulation substrate. The method includes depositing an insulatingmaterial on the semiconductor pattern to form an insulating materiallayer. The method also includes forming a gate electrode on theinsulating material layer. The method includes patterning the insulatingmaterial layer by using the gate electrode as an etching mask to form agate insulating layer and to expose a portion of the semiconductorpattern. The method includes treating the exposed semiconductor patternto form a channel region covered by the gate electrode, and to form asource region and a drain region facing each other with respect to thechannel region, wherein a carrier concentration of the source region andthe drain region is larger than a carrier concentration of the channelregion.

According to exemplary embodiments of the present invention, parasiticcapacitance between the gate electrode of the thin film transistor andthe source region or the drain region of the semiconductor layer may bedecreased and the characteristic of the thin film transistor may beimproved. Also, in the thin film transistor array panel including thethin film transistor, a kickback voltage may be reduced and a signaldelay and a distortion may be reduced.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a thin film transistor array panelaccording to exemplary embodiments of the present invention,

FIG. 2A is a cross-sectional view of a thin film transistor array panelaccording to exemplary embodiments of the present invention,

FIG. 2B is a top plan view of the thin film transistor array panel shownin FIG. 2A,

FIG. 3A is a cross-sectional view of a thin film transistor array panelaccording to exemplary embodiments of the present invention,

FIG. 3B is a top plan view of the thin film transistor array panel shownin FIG. 3A,

FIG. 4A is a cross-sectional view of a thin film transistor array panelaccording to exemplary embodiments of the present invention,

FIG. 4B is a top plan view of the thin film transistor array panel shownin FIG. 4A,

FIG. 5 is a cross-sectional view sequentially showing a manufacturingmethod of a thin film transistor array panel according to exemplaryembodiments of the present invention,

FIG. 6 is a cross-sectional view of a thin film transistor array panelaccording to exemplary embodiments of the present invention,

FIG. 7 is a top plan view of the thin film transistor array panel shownin FIG. 6,

FIG. 8 is a cross-sectional view sequentially showing a manufacturingmethod of a thin film transistor array panel according to exemplaryembodiments of the present invention,

FIG. 9 is a cross-sectional view of a thin film transistor array panelaccording to exemplary embodiments of the present invention,

FIG. 10 is a top plan view of the thin film transistor array panel shownin FIG. 9,

FIG. 11 is a cross-sectional view sequentially showing a manufacturingmethod of the thin film transistor array panel shown in FIG. 9 and FIG.10 according to an exemplary embodiment of the present invention,

FIG. 12 is a cross-sectional view of a thin film transistor array panelaccording to exemplary embodiments of the present invention,

FIG. 13 is a cross-sectional view (a) and a top plane view (b) of a thinfilm transistor array panel according to exemplary embodiments of thepresent invention,

FIG. 14 to FIG. 19 are cross-sectional views showing an exemplarymanufacturing process of the thin film transistor array panel shown inFIG. 13 according to exemplary embodiments of the present invention,

FIG. 20 is a cross-sectional view of a thin film transistor array panelaccording to exemplary embodiments of the present invention, and

FIG. 21 to FIG. 28 are cross-sectional views sequentially showing anexemplary manufacturing process of the thin film transistor array panelshown in FIG. 20 according to exemplary embodiments of the presentinvention.

FIGS. 29 and 30 are flowcharts of processes for manufacturing a thinfilm transistor array panel according to exemplary embodiments of thepresent invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention will be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsof the invention are shown. As those skilled in the art would realize,the described embodiments may be modified in various different ways, allwithout departing from the spirit or scope of the present invention.

In the drawings, the thickness of layers, films, panels, and regions maybe exaggerated for clarity. Like reference numerals designate likeelements throughout the specification. It will be understood that whenan element such as a layer, film, region, or substrate is referred to asbeing “on” another element, it can be directly on the other element orintervening elements may also be present. In contrast, when an elementis referred to as being “directly on” another element, there are nointervening elements present.

It will be understood that when an element or layer is referred to asbeing “on” or “connected to” another element or layer, it can bedirectly on or directly connected to the other element or layer, orintervening elements or layers may be present. In contrast, when anelement or layer is referred to as being “directly on” or “directlyconnected to” another element or layer, there are no interveningelements or layers present. It will be understood that for the purposesof this disclosure, “at least one of X, Y, and Z” can be construed as Xonly, Y only, Z only, or any combination of two or more items X, Y, andZ (e.g., XYZ, XYY, YZ, ZZ).

FIG. 1 is a cross-sectional view of a thin film transistor array panelaccording to exemplary embodiments of the present invention.

A gate line 121 including a gate electrode 124 may be positioned on asubstrate 110 including an insulating material such as plastic or glass.The gate line 121 (FIG. 2B) can transmit a gate signal including agate-on voltage Von and a gate-off voltage Voff.

The gate line 121 may be made of a material such as an aluminum-basedmetal of aluminum (Al) or aluminum alloys, a silver-based metal ofsilver (Ag) or silver alloys, a copper-based metal of copper (Cu) orcopper alloys, a molybdenum-based metal of molybdenum (Mo) or molybdenumalloys, chromium (Cr), tantalum (Ta), and titanium (Ti). In an example,the gate line 121 may be made of a multilayered structure including atleast two conductive layers having different physical properties.

A gate insulating layer 140 may be formed on the gate line 121. The gateinsulating layer 140 may include an insulating material such as siliconoxide (SiO_(X)), silicon nitride (SiN_(X)), or silicon oxynitride(SiON). The gate insulating layer 140 may be formed through a sputteringmethod.

A semiconductor layer including a channel region 154, a source region153, and a drain region 155 may be formed on the gate insulating layer140.

The channel region 154 overlaps the gate electrode 124. A boundarybetween the channel region 154 and the source region 153 or the drainregion 155 may be substantially aligned with an edge boundary of thegate electrode 124, or may be positioned inside or outside the edgeboundary of the gate electrode 124. For example, the characteristic ofthe edge boundary of the channel region 154 being substantially alignedwith the edge boundary of the gate electrode 124 may improve acharacteristic of the thin film transistor and preventing signal delayin the thin film transistor array panel.

The channel region 154 may include an oxide semiconductor. The oxidesemiconductor as a metal oxide semiconductor may be formed of an oxideof a metal such as zinc (Zn), indium (In), gallium (Ga), tin (Sn), andtitanium (Ti), or the metal such as zinc (Zn), indium (In), gallium(Ga), tin (Sn), titanium (Ti), and the oxide combination thereof. Forexample, the oxide semiconductor material may include at least one ofzinc oxide (ZnO), zinc-tin oxide (ZTO), zinc-indium oxide (ZIO), indiumoxide (InO), titanium oxide (TiO), indium-gallium-zinc oxide (IGZO), andindium-zinc-tin oxide (IZTO).

The source region 153 and the drain region 155 are positioned on bothsides with respect to the channel region 154 and are separated from eachother. By way of configuration, the source region 153 and the drainregion 155 may overlap the gate electrode 124. Alternatively, forexample, the source region 153 and the drain region 155 may not overlapthe gate electrode 124

The source region 153 and the drain region 155 are physically andelectrically connected to the channel region 154.

In some examples, the source region 153 and the drain region 155 includethe oxide semiconductor forming the channel region 154, however acarrier concentration of the source region 153 and the drain region 155may be different from the carrier concentration of the channel region154. For example, when the carrier concentration of the channel region154 is less than 10¹⁸ units/cm³, the carrier concentration of the sourceregion 153 and the drain region 155 is equal to or more than 10¹⁸units/cm³. As an exemplary embodiment, a gradient of the carrierconcentration may be formed in the boundary between the source region153 or the drain region 155 and the channel region 154.

According to exemplary embodiments of the present invention, the sourceregion 153 and the drain region 155 may include the oxide semiconductorforming the channel region 154 and a reduced oxide semiconductor. Forexample, the source region 153 and the drain region 155 may include theoxide semiconductor and at least one of fluorine (F), hydrogen (H), andsulfur (S). In this example, a concentration of at least one of fluorine(F), hydrogen (H), and sulfur (S) included in the source region 153 andthe drain region 155 may be equal to or more than 10¹⁵ units/cm³. Thegradient of at least one concentration of fluorine (F), hydrogen (H),and sulfur (S) may be formed in the boundary between the source region153 or the drain region 155 and the channel region 154.

The source region 153 and the drain region 155 may be formed by reducingthe oxide semiconductor forming the channel region 154 by a plasmatreatment. For example, the oxide semiconductor may be doped with atleast one of fluorine (F), hydrogen (H), and sulfur (S) by using a gasincluding at least one of fluorine (F), hydrogen (H), and sulfur (S) ina chamber, thereby forming the source region 153 and the drain region155 according to exemplary embodiments of the present invention.

The oxide semiconductor may be an n-type semiconductor such that thesource region 153 and the drain region 155 doped with at least one gasamong fluorine (F), hydrogen (H), and sulfur (S) become n+ layers. Inthis example, the source region 153 and the drain region 155 function asohmic contacts between the electrode and the semiconductor layer.

According to exemplary embodiments, the source region 153 and the drainregion 155 may function as a source electrode and a drain electrodehaving conductivity.

An etch stopper (referred to as an etching preventing layer) 164 may beformed on the channel region 154. Right and left edge boundaries of theetch stopper 164 may be substantially aligned with the right and leftedge boundaries of the channel region 154. Accordingly, the etch stopper164 may not substantially overlap the source region 153 or the drainregion 155.

The etch stopper 164 may cover the channels of the semiconductor 154such that damage to the channel of the thin film transistor by theetchant may be prevented in following processes. For example, the etchstopper 164 can prevent an impurity such as hydrogen (H) from beingdiffused into the semiconductor 154 from an insulating layer of apassivation layer 180 positioned on the semiconductor 154 or theoutside, thereby preventing a change of the characteristics of thesemiconductor 154.

In some examples, the thickness of the etch stopper 164 may be equal toor less than about 3000 Å, and the etch stopper 155 may be formed of theinorganic layer including at least one material of SiO_(X), SiN_(X),SiOC_(X), and SiON_(X), or the organic layer including the organicmaterial or a polymer organic material.

When the source region 153 and the drain region 155 perform the functionof the source electrode and the drain electrode, the gate electrode 124and the source region 153 and drain region 155 of the semiconductorlayer form a thin film transistor (TFT) along with the channel region154, and a channel of the thin film transistor may be formed in thechannel region 154.

A channel length L of the thin film transistor may be defined by adistance between the source region 153 and the drain region 155, thatis, a horizontal direction width of the channel region 154. Also, achannel width (not shown) of the thin film transistor may be defined bya length of the boundary between the source region 153 or the drainregion 155 and the channel region 154. According to exemplaryembodiments of the present invention, the channel length L of the thinfilm transistor depends on the horizontal direction width of the etchstopper 164, and when forming the etch stopper 164 by a photolithographyprocess, the channel length L may be reduced to an exposure limit of alight exposer. For example, when the exposure limit of the light exposeris about 3 μm, the channel length (L) of the thin film transistor may bereduced to about 3 μm such that mobility of the thin film transistor maybe increased, thereby improving the characteristic of the thin filmtransistor.

Also, according to exemplary embodiments of the present invention, thechannel length L of the thin film transistor is the about same as thehorizontal direction width of the etch stopper 164 such that the channellength L of the thin film transistor may be controlled by controllingthe horizontal direction width of the etch stopper 164. Accordingly, theposition of the boundary between the channel region 154 and the sourceregion 153 or the drain region 155 for the edge boundary of the gateelectrode 124 may be determined. It is contemplated that the boundarybetween the channel region 154 and the source region 153 or the drainregion 155 substantially aligned with or is positioned outside the edgeboundary of the gate electrode 124, the source region 153 and the drainregion 155 do not substantially overlap the gate electrode 124 such thatthe parasitic capacitance between the gate electrode 124 and the sourceregion 153 or the drain region 155 may be remarkably reduced.Accordingly, in the thin film transistor array panel, the kickbackvoltage by the parasitic capacitance between the gate electrode 124 andthe source region 153 or the drain region 155, and the signal delay or adistortion, may be reduced. Accordingly, power consumption may bereduced, the thickness of a signal transmitting wiring (not shown) suchas the data line may be further reduced, and freedom for wiring materialselection may be increased.

The passivation layer 180 is positioned on the source region 153, thedrain region 155, and the etch stopper 164. The passivation layer 180may be made of an insulating material such as silicon oxide (SiO_(X)),silicon nitride (SiN_(X)), silicon nitroxide (SiON), and fluorine-dopedsilicon oxide (SiOF).

FIG. 2A is a cross-sectional view of a thin film transistor array panelaccording to exemplary embodiments of the present invention, FIG. 2B isa top plan view of the thin film transistor array panel shown in FIG.2A, FIG. 3A is a cross-sectional view of a thin film transistor arraypanel according to exemplary embodiments of the present invention, andFIG. 3B is a top plan view of the thin film transistor array panel shownin FIG. 3A.

The exemplary embodiments shown in FIG. 2A and FIG. 2B may be the sameas most of the exemplary embodiment shown in FIG. 1, however it mayfurther include a data line 171 connected to the source region 153 and apixel electrode 191 connected to the drain region 155.

The data line 171 may transmit a data signal and cross the gate line 121while being insulated from the gate line 121. The data line 171 iselectrically connected to the source region 153.

Referring to FIG. 2A and FIG. 2B, for example, the data line 171directly contacts the source region 153 to be electrically connectedthereto.

In this example, the data line 171 may be positioned under thepassivation layer 180. Also, the data line 171 may include a protrusion(not shown) protruded toward the source region 153, and the protrusionmay contact the source region 153.

Referring to FIG. 3A and FIG. 3B, the data line 171 may be electricallyconnected to the source region 153 through a bridge 88. In this example,the data line 171 may be disposed under the passivation layer 180, andthe passivation layer 180 may include a contact hole 187 exposing thedata line 171 and a contact hole 188 exposing the source region 153. Thebridge 88 may electrically connect the data line 171 and the sourceregion 153 through the contact holes 187 and 188. The data line 171 maybe disposed between the gate insulating layer 140 and the passivationlayer 180, and may be disposed on the passivation layer 180. When thedata line 171 is disposed under the passivation layer 180, the bridge 88may be formed in the same layer and with the same material as the pixelelectrode 191.

The pixel electrode 191 is positioned on the passivation layer 180 andmay be made of a transparent conductive material such as ITO and IZO.The pixel electrode 191 may be electrically connected to the drainregion 155 through the contact hole 185 of the passivation layer 180.The pixel electrode 191 receives the data voltage from the drain region155, thereby displaying images.

When the thin film transistor array panel according to exemplaryembodiments of the present invention is included in the liquid crystaldisplay, the pixel electrode 191 forms an electric field to a liquidcrystal layer (not shown) along with an opposed electrode (not shown) tocontrol an arrangement direction of liquid crystal molecules, therebydisplaying the image. When the thin film transistor array panelaccording to exemplary embodiments of the present invention is includedin an organic light emitting device, an emission layer (not shown) ispositioned between the pixel electrode 191 and the opposed electrode(not shown) thereby forming a light emitting diode (LED).

In some exemplary embodiments of the present invention, it is notnecessary for the data line 171 or the pixel electrode 191 to directlycontact the channel region 154 of the thin film transistor. Accordingly,a distance may be somehow provided between the data line 171 and thepixel electrode 191, and the channel region 154, such that a metalcomponent of the data line 171 may be prevented from being diffused intothe channel region 154, particularly when the data line 171 includes ametal such as copper (Cu). Accordingly, the characteristic deteriorationof the thin film transistor may be prevented.

FIG. 4A is a cross-sectional view of a thin film transistor array panelaccording to exemplary embodiments of the present invention, and FIG. 4Bis a top plan view of the thin film transistor array panel shown in FIG.4A.

The exemplary embodiments shown in FIG. 4A and FIG. 4B may be the sameas most of the exemplary embodiment of FIG. 1, however a sourceelectrode 173 on the source region 153, a drain electrode 175 on thedrain region 155, and a pixel electrode 191 electrically connected tothe drain electrode 175 may be further included. In this example, thesource electrode 173 directly contacts the source region 153 to beelectrically connected thereto, and the drain electrode 175 directlycontacts the drain region 155 to be electrically connected thereto.

If the oxide semiconductor region is reduced by a method such as plasmatreatment to form the source region 153 and the drain region 155, thesource region 153 and the drain region 155 doped with at least one gasof fluorine (F), hydrogen (H), and sulfur (S) become the n+ layer suchthat they may function as the ohmic contact between the source electrode173 and the drain electrode 175, and the channel layer 154.

In FIG. 4A, for example, the source electrode 173 and the drainelectrode 175 may be thicker than the source region 153 and the drainregion 155. In another exemplary embodiment, the source electrode 173and the drain electrode 175 may have the thickness that is equal to orthinner than that of the source region 153 and the drain region 155.

The source electrode 173 transmits the data signal and is connected tothe data line 171. For example, the source electrode 173 may be aportion protruded from a portion of the data line 171, as exemplarilyshown in FIG. 4B. As another example, the source electrode 173 may beseparately formed from the data line 171 and may be connected to thedata line 171, similar to arrangement of FIGS. 3A and 3B

The pixel electrode 191 may be positioned on the passivation layer 180and may be formed of the transparent conductive material such as ITO andIZO. The pixel electrode 191 is electrically connected to the drainelectrode 175 through the contact hole 185 of the passivation layer 180.The pixel electrode 191 receives the data voltage from the drainelectrode 175 thereby controlling the display of an image.

The source electrode 173 and the drain electrode 175 may be made of amaterial such as an aluminum-based metal of aluminum (Al) or aluminumalloys, a silver-based metal of silver (Ag) or silver alloys, acopper-based metal of copper (Cu) or copper alloys, a molybdenum-basedmetal of molybdenum (Mo) or molybdenum alloys, chromium (Cr), tantalum(Ta), and titanium (Ti). For example, as the molybdenum alloy, there areMo—Nb and Mo—Ti. The source electrode 173 and the drain electrode 175may be made of a transparent conductive material such as ITO, IZO, andAZO. The source electrode 173 and the drain electrode 175 may be made ofa multilayered structure including at least two conductive layers (notshown). For example, the source electrode 173 and the drain electrode175 may have a multilayered structure of Mo/Al/Mo, Mo/Al, Mo/Cu,CuMn/Cu, or Ti/Cu.

In the present exemplary embodiments, it is not necessary for the sourceelectrode 173 and the drain electrode 175 to contact the channel region154. Accordingly, a distance may be somehow provided between the sourceelectrode 173 and the drain electrode 175, and the channel region 154,such that a metal component of the source electrode 173 and the drainelectrode 175 may be prevented from being diffused into the channelregion 154, particularly when the source electrode 173 and the drainelectrode 175 include the metal such as copper (Cu). Accordingly, thecharacteristic deterioration of the thin film transistor may beprevented.

FIG. 5 is a cross-sectional view sequentially showing a manufacturingmethod of a thin film transistor array panel according to exemplaryembodiments of the present invention.

In the present exemplary embodiments, the thin film transistor arraypanel shown in FIG. 4A and FIG. 4B is described as an example, howeverit is not limited thereto, and the manufacturing method according anexemplary embodiments of the present invention may be equally applied todifferent various exemplary embodiments.

Referring to FIG. 5( a), a conductive material such as a metallicmaterial is deposited and patterned on an insulation substrate 110 madeof glass or plastic to form a gate electrode 124.

A gate insulating layer 140 including the insulating material such assilicon oxide (SiO_(X)), silicon nitride (SiN_(X)), or silicon nitroxide(SiON) is deposited on the gate electrode 124.

The semiconductor layer (not shown) made of the oxide semiconductormaterial such as zinc oxide (ZnO), zinc-tin oxide (ZTO), zinc-indiumoxide (ZIO), indium oxide (InO), titanium oxide (TiO),indium-gallium-zinc oxide (IGZO), and indium-zinc-tin oxide (IZTO) iscoated on the gate insulating layer 140, and then a photosensitive filmsuch as photoresist is coated and exposed to form a photosensitive filmpattern 51.

The semiconductor material layer is etched by using the photosensitivefilm pattern 51 as a mask to form a semiconductor pattern 150.

Referring to FIG. 5( b), the photosensitive film pattern 51 is removedand an etch stopper 164 is formed on the semiconductor pattern 150. Theetch stopper 164 overlaps the gate electrode 124 and intersects thecenter portion of the semiconductor pattern 150 to overlap it, andportions of the semiconductor pattern 150 that are not covered by theetch stopper 164 are positioned to be separated from each other with theetch stopper 164 interposed therebetween. The etch stopper 164 may beformed by depositing the inorganic layer including at least one materialof SiO_(X), SiN_(X), SiOC_(X), and SiON_(X), or the organic layerincluding the organic material or a polymer organic material by achemical vapor deposition (CVD) or a sputtering method and patterningthrough a photo-process. In this example, the dry etch method may beused, and an etching gas having an etch rate that does not etch thesemiconductor pattern 150 may be used.

Referring to FIG. 5( c), portions of the semiconductor pattern 150exposed by the etch stopper 164 are treated to form the source region153 and the drain region 155. Also, the semiconductor pattern 150covered by the etch stopper 164 becomes the channel region 154.Accordingly, the gate electrode 124, the source region 153, and thedrain region 155 form the thin film transistor along with the channelregion 154.

As methods for treating the exposed semiconductor pattern 150, forexample, there are a heat treatment in a reduction atmosphere in achamber, and a plasma treatment using a gas plasma such as such ashydrogen (H₂), helium (He), phosphine (PH₃), ammonia (NH₃), silane(SiH₄), methane (CH₄), acetylene (C₂H₂), diborane (B₂H₆), carbon dioxide(CO₂), germane (GeH₄), hydrogen selenide (H₂Se), hydrogen sulfide (H₂S),argon (Ar), nitrogen (N₂), nitrogen oxide (N₂O), and fluoroform (CHF₃).

Particularly, according to exemplary embodiments of the presentinvention, the method of doping or reducing the exposed semiconductorpattern 150 with at least one of fluorine (F), hydrogen (H), and sulfur(S) by using the gas including at least one of tetrafluoromethane (CF₄),nitrogen trifluoride (NF₃), sulfur hexafluoride (SF₆), and methane (CH₄)is used. Accordingly, as described above, the source region 153 and thedrain region 155 including at least one of fluorine (F), hydrogen (H),and sulfur (S) may be formed along with the oxide semiconductor of thechannel region 154. In this example, at least one concentration offluorine (F), hydrogen (H), and sulfur (S) doped to the source region153 and the drain region 155 may be equal to or more than about 10¹⁵units/cm³.

Referring to FIG. 5( d), a source electrode 173 and a drain electrode175 may be further formed on the source region 153 and the drain region155.

Referring to FIG. 5( e), an insulating material is coated on the sourceelectrode 173 and the drain electrode 175, the source region 153 and thedrain region 155, and the etch stopper 164 to form a passivation layer180. The passivation layer 180 is patterned to form a contact hole 185exposing the drain electrode 175.

As shown in FIG. 2A, FIG. 2B, FIG. 3A, FIG. 3B, FIG. 4A, and FIG. 4B, apixel electrode 191 electrically connected to the drain electrode 175 orthe drain region 155 may be formed on the passivation layer 180.

In the thin film transistor manufactured by the manufacturing methodaccording to exemplary embodiments of the present invention, the widthof the etch stopper 164 is controlled in the exposure limitation suchthat the source region 153 and the drain region 155 of the semiconductorlayer may be formed to not substantially overlap the gate electrode 124,thereby reducing the parasitic capacitance between the gate electrode124 and the source region 153 or the drain region 155 and improving anon/off characteristic as the switching element of the thin filmtransistor. Also, the power consumption of the thin film transistor maybe reduced, the thickness of the signal transmitting wiring may bereduced, and the freedom of the wiring material selection may beincreased.

Also, the channel length L of the thin film transistor may be reduced tothe exposure limitation of the light exposer such that the mobility maybe increased, thereby improving the characteristic of the thin filmtransistor.

The same constituent elements as in the exemplary embodiments describedabove use the same reference numerals and the same description may beomitted to avoid unnecessarily obscuring the present invention.

FIG. 6 is a cross-sectional view of a thin film transistor array panelaccording to exemplary embodiments of the present invention, and FIG. 7is a top plan view of the thin film transistor array panel shown in FIG.6.

The present exemplary embodiment is the same as most of the thin filmtransistor array panel according to the exemplary embodiments shown inFIG. 2A to FIG. 4B except for a linear etch stopper 161 extendingparallel to the gate line 121 and connected to an etch stopper 164.

An edge boundary of the linear etch stopper 161 including the etchstopper 164 may be aligned with the edge boundary of the gate line 121including the gate electrode 124, or may be positioned inside or outsideof the edge boundary of the gate line 121. For example, the plane shapeof the linear etch stopper 161 including the etch stopper 164 may besubstantially the same as or similar to the plane shape of the gate line121 including the gate electrode 124.

The channel region 154 is covered by the etch stopper 164, and the edgeboundary of the channel region 154, for example, the boundary betweenthe channel region 154 and the source region 153 or the drain region155, may substantially be aligned with or may be positioned slightlyinside the edge boundary of the etch stopper 164.

According to the present exemplary embodiments, the area where the gateelectrode 124 overlaps the source region 153 or the drain region 155 maybe minimized such that the parasitic capacitance between the gateelectrode 124 and the source region 153 or the drain region 155 may beremarkably reduced.

FIG. 8 is a cross-sectional view sequentially showing a manufacturingmethod of a thin film transistor array panel according to exemplaryembodiments of the present invention.

Referring to FIG. 8( a), a conductive material such as the metal isdeposited and patterned on an insulation substrate 110 made of glass orplastic to form a gate electrode 124.

A gate insulating layer 140 including the insulating material such assilicon oxide (SiO_(X)), silicon nitride (SiN_(X)), or silicon nitroxide(SiON) is deposited on the gate electrode 124.

A semiconductor pattern 150 including the oxide semiconductor materialis formed on the gate insulating layer 140, and the inorganic layerincluding at least one material of SiO_(X), SiN_(X), SiOC_(X), andSiON_(X), or the organic layer including the organic material or apolymer organic material, is deposited by a chemical vapor deposition(CVD) or sputtering method to form an etch stopper layer 160.

A photosensitive film 50 such as photoresist is coated on the etchstopper layer 160 and light is irradiated from a rear (bottom) side ofthe insulation substrate 110. In this example, the photosensitive film50 has positive photosensitivity such that an exposed portion thereof isremoved. Thus, the photosensitive film 50 that is not covered by theopaque gate electrode 124 is exposed, thereby being removed.

Referring to FIG. 8( b), the exposed photosensitive film 50 is removedto form a photosensitive film pattern 52 corresponding to the gateelectrode 124. In this example, the edge boundary of the photosensitivefilm pattern 52 may be aligned with the edge boundary of the gateelectrode 124, and may be positioned slightly inside or outside the edgeboundary of the gate electrode 124. This may be determined by variousdesign factors such as a wavelength of the light used in the lightexposer, or a kind of material passing the light.

Referring to FIG. 8( c), the etch stopper layer 160 is etched by usingthe photosensitive film pattern 52 as a mask to form the etch stopper164 intersecting and covering the semiconductor pattern 150.

Referring to FIG. 8( d), two portions of the semiconductor pattern 150that are not covered by the etch stopper 164 and are exposed are dopedwith ions to form the source region 153 and the drain region 155 havingconductivity. The semiconductor pattern 150 covered by the etch stopper164 becomes the channel region 154. Accordingly, the gate electrode 124,the source region 153, and the drain region 155 form the thin filmtransistor along with the channel region 154.

The method of treating the exposed semiconductor pattern 150 is the sameas that of the above-described exemplary embodiments such that thedetailed description may be omitted.

Referring to FIG. 8( e), a source electrode 173 and a drain electrode175 may be further formed on the source region 153 and the drain region155.

Referring to FIG. 8( f), an insulating material is coated on the sourceelectrode 173 and the drain electrode 175, the source region 153 and thedrain region 155, and the etch stopper 164 to form a passivation layer180. The passivation layer 180 is patterned to form a contact hole 185exposing the drain electrode 175, and as shown in FIG. 6 and FIG. 7, apixel electrode 191 electrically connected to the drain electrode 175 orthe drain region 155 may be formed on the passivation layer 180.

FIG. 9 is a cross-sectional view of a thin film transistor array panelaccording to exemplary embodiments of the present invention, and FIG. 10is a top plan view of the thin film transistor array panel shown in FIG.9.

The present exemplary embodiment is the same as most of the thin filmtransistor array panel according to the exemplary embodiment shown inFIG. 2A to FIG. 4B except for an upper gate electrode 194 facing thegate electrode 124 on the passivation layer 180. The upper gateelectrode 194 may include the same material as the pixel electrode 191,and may be simultaneously formed with the pixel electrode 191.

Referring to FIG. 10, the upper gate electrode 194 contacts the gateline 121 to be electrically connected thereto, thereby receiving thegate signal from the gate line 121. In this example, the passivationlayer 180 and the gate insulating layer 140 have a contact hole 184exposing the gate line 121, and the upper gate electrode 194 may beconnected to the gate line 121 through the contact hole 184. Thehorizontal direction width of the upper gate electrode 194 may be equalto or less than the horizontal direction width of the channel region154.

FIG. 11 is a cross-sectional view sequentially showing a manufacturingmethod of the thin film transistor array panel shown in FIG. 9 and FIG.10 according to exemplary embodiments of the present invention.

The manufacturing method of the thin film transistor according to thepresent exemplary embodiments is the same as most of the manufacturingmethod of the thin film transistor according to the exemplary embodimentshown in FIG. 8 such that the detailed description may be omitted.However, referring to FIG. 11( f), when forming the pixel electrode 191with the transparent conductive material such as ITO and IZO, the uppergate electrode 194 positioned on the channel region 154 may be formed atthe same time.

Referring to FIG. 12, the thin film transistor and the thin filmtransistor array panel according to an exemplary embodiment of thepresent invention will be described.

FIG. 12 is a cross-sectional view of a thin film transistor array panelaccording to exemplary embodiments of the present invention.

Referring to FIG. 12, the present exemplary embodiment is the same asmost of the thin film transistor array panel according to the exemplaryembodiment shown in FIG. 4A and FIG. 4B, however portions of the sourceelectrode 173 and the drain electrode 175 may not directly contact thesource region 153 and the drain region 155 and may be positioned on thepassivation layer 180. In this example, the passivation layer 180 has acontact hole 183 exposing the source region 153 and a contact hole 185exposing the drain region 155, and the source electrode 173 and thedrain electrode 175 may be respectively electrically connected to thesource region 153 and the drain region 155 through the contact holes 183and 185 of the passivation layer 180.

FIG. 13 is a cross-sectional view (a) and a top plane view (b) of a thinfilm transistor array panel according to exemplary embodiments of thepresent invention.

Referring to FIG. 13( a), a light blocking film 70 may be positioned onan insulation substrate 110. The light blocking film 70 prevents lightfrom reaching an oxide semiconductor to be deposited later such that acharacteristic of the oxide semiconductor as a semiconductor may beprevented from being lost. Accordingly, the light blocking film 70 ismade of a material that does not transmit light of a wavelength bandthat is not to reach the oxide semiconductor. The light blocking film 70may be made of an organic insulating material, an inorganic insulatingmaterial, or a conductive material such as a metal, and may be formedwith a single layer or multiple layers. However, the light blocking film70 may be omitted by way of a configuration. For example, when the lightis not irradiated under the insulation substrate 110, for example whenthe thin film transistor is used for an organic light emitting device,the light blocking film 70 may be omitted.

A buffer layer 120 may be positioned on the light blocking film 70. Thebuffer layer 120 may include an insulating oxide such as silicon oxide(SiO_(X)), aluminum oxide (Al₂O₃), hafnium oxide (HfO₃), and yttriumoxide (Y₂O₃). The buffer layer 120 prevents an impurity from theinsulation substrate 110 from flowing into the semiconductor to bedeposited later, thereby protecting the semiconductor and improving aninterface characteristic of the semiconductor.

A semiconductor layer including the channel region 154, the sourceregion 153, and the drain region 155 is positioned on the buffer layer120. When the light blocking film 70 exists, the channel region 154 maybe covered by the light blocking film 70. The description of the channelregion 154, the source region 153, and the drain region 155 is the sameas that of the above exemplary embodiments such that the detaileddescription is omitted.

Particularly, the source region 153 and the drain region 155 include thesame material as the oxide semiconductor forming the channel region 154,however the carrier concentration of the source region 153 and the drainregion 155 is different from the carrier concentration of the channelregion 154. For example, when the carrier concentration of the channelregion 154 is less than about 10¹⁸ units/cm³, the carrier concentrationof the source region 153 and the drain region 155 is equal to or morethan about 10¹⁸ units/cm³. The gradient of the carrier concentration isformed in the boundary between the source region 153 or the drain region155 and the channel region 154.

According to exemplary embodiments of the present invention, the sourceregion 153 and the drain region 155 may include the oxide semiconductorand may be doped with at least one of fluorine (F), hydrogen (H), andsulfur (S). In this example, a concentration of at least one of fluorine(F), hydrogen (H), and sulfur (S) included in the source region 153 andthe drain region 155 is equal to or more than about 10¹⁵ units/cm³. Thegradient of at least one concentration of fluorine (F), hydrogen (H),and sulfur (S) is formed in the boundary between the source region 153or the drain region 155 and the channel region 154.

A gate insulating layer 142 is positioned on the channel region 154. Thegate insulating layer 142 may cover the channel region 154. Also, thegate insulating layer 142 may not substantially overlap the sourceregion 153 or the drain region 155 by way of configurations.

The gate insulating layer 142 may be formed as a singular layer or amultilayer of at least two layers. When the gate insulating layer 142 isthe singular layer, the insulating layer 142 may include the insulatingoxide such as silicon oxide (SiO_(X)), aluminum oxide (Al₂O₃), hafniumoxide (HfO₃), and yttrium oxide (Y₂O₃). The insulating layer 142 mayimprove an interface characteristic of the channel region 154, and mayprevent the impurity from penetrating into the channel region 154.

When the gate insulating layer 142 is the multilayer, the gateinsulating layer 142 may include a lower layer 142 a and an upper layer142 b shown in FIG. 13( a). The lower layer 142 a includes theinsulating oxide such as silicon oxide (SiO_(X)), aluminum oxide(Al₂O₃), hafnium oxide (HfO₃), and yttrium oxide (Y₂O₃) such that theinterface characteristic of the semiconductor 134 may be improved andthe penetration of the impurity into the semiconductor 134 may beprevented. The upper layer 142 b may be made of various insulatingmaterials such as silicon nitride (SiN_(X)) and silicon oxide (SiO_(X)).

A gate electrode 124 is positioned on the gate insulating layer 142. Anedge boundary of the gate electrode 124 and the edge boundary of thegate insulating layer 142 are arranged to substantially aligned.

Referring to FIG. 13( a) and FIG. 13( b), the gate electrode 124includes a portion overlapping the channel region 154, and the channelregion 154 is covered by the gate electrode 124. The source region 153and the drain region 155 are positioned at both sides of the channelregion 154 with respect to the gate electrode 124, and the source region153 and the drain region 155 may not substantially overlap the gateelectrode 124. Accordingly, the parasitic capacitance between the gateelectrode 124 and the source region 153 or the parasitic capacitancebetween the gate electrode 124 and the drain region 155 may bedecreased.

According to exemplary embodiments of the present invention, theboundary between the channel region 154 and the source region 153 or theboundary between the channel region 154 and the drain region 155 maysubstantially be aligned with the edge boundary of the gate electrode124 and the gate insulating layer 142. However, the boundary between thechannel region 154 and the source region 153 or the drain region 155 maybe positioned slightly more inward than the edge boundary of the gateelectrode 124 and the gate insulating layer 142.

The gate electrode 124, the source region 153, and the drain region 155form the thin film transistor along with the channel region 154, and thechannel of the thin film transistor is formed in the channel region 154.

A passivation layer 180 is positioned on the gate electrode 124, thesource region 153, the drain region 155, and the buffer layer 120. Thepassivation layer 180 may include the contact hole 183 exposing thesource region 153 and the contact hole 185 exposing the drain region155.

The source electrode 173 and the drain electrode 175 may be positionedon the passivation layer 180. The source electrode 173 is electricallyconnected to the source region 153 of the thin film transistor throughthe contact hole 183 of the passivation layer 180, and the drainelectrode 175 is electrically connected to the drain region 155 of thethin film transistor through the contact hole 185 of the passivationlayer 180.

Differently from this, for example, a color filter (not shown) or anorganic layer (not shown) made of an organic material may be furtherpositioned on the passivation layer 180, and the source electrode 173and the drain electrode 175 may be further positioned thereon.

FIG. 14 to FIG. 19 are cross-sectional views sequentially showing amanufacturing method of the thin film transistor array panel shown inFIG. 13 according to exemplary embodiments of the present invention,

Referring to FIG. 14, the light blocking film 70 made of the organicinsulating material, the inorganic insulating material, or theconductive material such as the metal is formed on the insulationsubstrate 110 made of glass or plastic. The forming of the lightblocking film 70 may be omitted by way of configurations.

Referring to FIG. 3, the buffer layer 120 made of the insulatingmaterial including the oxide such as silicon oxide (SiO_(X)), aluminumoxide (Al₂O₃), hafnium oxide (HfO₃), and yttrium oxide (Y₂O₃) is formedon the light blocking film 70 by a chemical vapor deposition (CVD)method. A thickness of the buffer layer 120 is in a range from about 500Å to about 1 μm, but is not limited thereto.

The semiconductor layer made of the oxide semiconductor material such aszinc oxide (ZnO), zinc-tin oxide (ZTO), zinc-indium oxide (ZIO), indiumoxide (InO), titanium oxide (TiO), indium-gallium-zinc oxide (IGZO), andindium-zinc-tin oxide (IZTO) is coated on the buffer layer 120, and thena photosensitive film such as a photoresist is coated thereon. Next, thephotosensitive film is exposed to form a photosensitive film pattern 53.The photosensitive film pattern 53 may overlap at least a portion of thelight blocking film 70.

The semiconductor layer is etched by using the photosensitive filmpattern 53 as a mask to form a semiconductor pattern 150.

As shown in FIG. 15, a gate insulating layer 140 is formed on thesemiconductor pattern 150 and the buffer layer 120. The gate insulatinglayer 140 may be formed with the singular layer including the insulatingoxide of silicon oxide (SiO_(X)), or as shown in FIG. 5, may be formedwith the multilayer including a lower layer 140 a including theinsulating oxide such as silicon oxide (SiO_(X)) and an upper layer 140b including the insulating material. The thickness of the gateinsulating layer 140 may be in a range from about 1000 Å to about 5000Å, but is not limited thereto.

Referring to FIG. 16, a conductive material such as the metal isdeposited on the gate insulating layer 140 and is patterned to form thegate electrode 124. The gate electrode 124 is formed to traverse thecenter portion of the semiconductor pattern 150 such that two portionsof the semiconductor pattern 150 positioned on both sides of theoverlapping portion of the gate electrode 124 and the semiconductorpattern 150 are not covered by the gate electrode 124.

Referring to FIG. 17, the gate insulating layer 140 is patterned byusing the gate electrode 124 as an etching mask to form the gateinsulating layer 142. The gate insulating layer 142 may be made of thesingular layer, or includes the lower layer 142 a including theinsulating oxide and the upper layer 142 b including the insulatingmaterial.

Accordingly, the gate electrode 154 and the insulating layer 142 mayhave substantially the same plane shape. Also, the two portions of thesemiconductor pattern 132 that are not covered by the gate electrode 154are exposed.

Referring to FIG. 18, the two exposed portion of the semiconductorpattern 132 are processed thereby forming the source region 153 and thedrain region 155 having conductivity. The treatment method of thesemiconductor pattern 150 is the same as that of the above exemplaryembodiments such that the detailed description is omitted.

Particularly, according to exemplary embodiments of the presentinvention, the method of doping or reducing the exposed semiconductorpattern 150 with at least one of fluorine (F), hydrogen (H), and sulfur(S) by using the gas including at least one of tetrafluoromethane (CF₄),nitrogen trifluoride (NF₃), sulfur hexafluoride (SF₆), and methane (CH₄)is used. At least one concentration of fluorine (F), hydrogen (H), andsulfur (S) doped to the source region 153 and the drain region 155 maybe equal to or more than about 10¹⁵ units/cm³, and the gradient of atleast one concentration of fluorine (F), hydrogen (H), and sulfur (S)may be formed in the boundary between the source region 153 or the drainregion 155 and the channel region 154.

Also, the semiconductor pattern 150 that is covered by the insulatinglayer 142 and is not reduced becomes the channel region 154.Accordingly, the gate electrode 124, the source region 153, and thedrain region 155 form the thin film transistor along with the channelregion 154.

Referring to FIG. 19, the insulating material is coated on the gateelectrode 124, the source region 153, the drain region 155, and thebuffer layer 120 to form the passivation layer 160. Next, thepassivation layer 180 is patterned to form a contact hole 183 exposingthe source region 153 and a contact hole 185 exposing the drain region155.

Finally, as shown in FIG. 13, the source electrode 173 and the drainelectrode 175 may be formed on the passivation layer 160.

In the thin film transistor according to exemplary embodiments of thepresent invention, the source region 153 and the drain region 155 do notsubstantially overlap the gate electrode 124 such that the parasiticcapacitance between the gate electrode 124 and the source region 153 orthe drain region 155 may be remarkably reduced. Accordingly, the on/offcharacteristic as the switching element of the thin film transistor maybe improved.

FIG. 20 is a cross-sectional view of a thin film transistor array panelaccording to exemplary embodiments of the present invention.

Referring to FIG. 20, a light blocking film 70 and a data line 115transmitting a data signal may be positioned on the insulation substrate110. The data line 115 may be made of the conductive material of themetal such as aluminum (Al), silver (Ag), copper (Cu), molybdenum (Mo),chromium (Cr), tantalum (Ta), and titanium (Ti), or alloys thereof.

A buffer layer 120 is positioned on the light blocking film 70 and thedata line 115, and a channel region 154, a source region 153, and adrain region 155 are positioned thereon.

The semiconductor 154 may include the oxide semiconductor material. Whenthe light blocking film 70 exists, the semiconductor 154 may be coveredby the light blocking film 70.

The source region 153 and the drain region 155 are positioned at bothsides with respect to the channel region 154 to face each other, and areseparated from each other. Also, the source region 153 and the drainregion 155 are connected to the channel region 154. The description forthe channel region 154, the source region 153, and the drain region 155of the above-described exemplary embodiments may be equally applied tothe present exemplary embodiments.

A gate insulating layer 142 is positioned on the channel region 154. Thegate insulating layer 142 may cover the channel region 154. Also, thegate insulating layer 142 may almost not overlap the source region 153or the drain region 155.

A gate electrode 124 is positioned on the gate insulating layer 142. Theedge boundary of the gate electrode 124 and the edge boundary of thegate insulating layer 142 may be arranged to substantially be aligned.

The gate electrode 124 includes a portion overlapping the channel region154, and the channel region 154 is covered by the gate electrode 124.The source region 153 and the drain region 155 are positioned at bothsides of the channel region 154 with respect to the gate electrode 124,and the source region 153 and the drain region 155 may not substantiallyoverlap the gate electrode 154. Accordingly, the parasitic capacitancebetween the gate electrode 124 and the source region 153 or theparasitic capacitance between the gate electrode 124 and the drainregion 155 may be substantially decreased.

A passivation layer 180 a is positioned on the gate electrode 124, thesource region 153, the drain region 155, and the buffer layer 120, andan organic layer 180 b may be further positioned thereon.

The organic layer 180 b may include an organic insulating material or acolor filter material. The surface of the organic layer 180 b may beflat.

The passivation layer 180 a and the organic layer 180 b have the contacthole 183 exposing the source region 153 and the contact hole 185exposing the drain region 155. Also, the buffer layer 120, thepassivation layer 180 a, and the organic layer 180 b may have a contacthole 181 exposing the data line 115.

The source electrode 173 and the drain electrode 175 may be positionedon the organic layer 180 b. The source electrode 173 may be electricallyconnected to the source region 153 through the contact hole 183, and thedrain electrode 175 may be electrically connected to the drain region155 through the contact hole 185. Also, the source electrode 173 may beconnected to the data line 115 through the contact hole 181.Accordingly, the source electrode 133 may receive the data signal fromthe data line 115. Meanwhile, the drain electrode 175 may form a pixelelectrode thereby controlling image display, or it may be connected toan additional pixel electrode (not shown).

Next, a manufacturing method of the thin film transistor array panelshown in FIG. 20 according to an exemplary embodiment of the presentinvention will be described with reference to FIG. 21 to referring toFIG. 28 as well as FIG. 20.

FIG. 21 to FIG. 28 are cross-sectional views sequentially showing amanufacturing method of the thin film transistor array panel shown inFIG. 20 according to an exemplary embodiment of the present invention.

Firstly, referring to FIG. 21, a light blocking film 70 made of theorganic insulating material, the inorganic insulating material, or theconductive material such as the metal is formed on an insulationsubstrate 110. The formation of the light blocking film 70 may beomitted by way of configurations.

The metal is deposited and patterned on the insulation substrate 110 toform a data line 115. The formation sequence of the light blocking film70 and the data line 115 may be exchanged.

Referring to FIG. 22, a buffer layer 120, a semiconductor material layer159, an insulating material layer 149, and a gate layer 129 aresequentially deposited on the light blocking film 70 and the data line115.

The semiconductor material layer 159 may be formed by depositing theoxide semiconductor material such as zinc oxide (ZnO), zinc-tin oxide(ZTO), zinc-indium oxide (ZIO), indium oxide (InO), titanium oxide(TiO), indium-gallium-zinc oxide (IGZO), and indium-zinc-tin oxide(IZTO).

The insulating material layer 149 may be formed of the insulatingmaterial including the insulating oxide such as silicon oxide (SiO_(X)).

The gate layer 129 may be formed by depositing the conductive materialsuch as aluminum (Al).

A photosensitive film of the photoresist is coated on the gate layer 129and is exposed to form a photosensitive film pattern 54. Thephotosensitive film pattern 54 includes, as shown in FIG. 22, a firstportion 54 a having a relatively thin thickness and a second portion 54b having a relatively thick thickness. The first portion 54 a of thephotosensitive film pattern 54 may be positioned at the portionoverlapping the light blocking film 70. Also, a pair of second portions54 b that are separated and face each other with respect to the firstportion 54 a are connected to both sides of the first portion 54 a ofthe photosensitive film pattern 54.

The photosensitive film pattern 54 may be formed by exposing through aphotomask (not shown) including a transflective region. For example, thephotomask for forming the photosensitive film pattern 54 may include atransmission region transmitting light, a light blocking region wherelight is not transmitted, and a transflective region where light ispartially transmitted. The transflective region may be formed by using aslit or a translucent layer.

If the exposure is performed by the photomask including thetransflective region, in a case of using a negative photosensitive film,the portion corresponding to the transmission region of the photomask isirradiated with the light such that the photosensitive film remainsthereby forming the first portion 54 a having a thick thickness, theportion corresponding to the light blocking region of the photomask isnot irradiated with the light such that the photosensitive film isremoved, and the portion corresponding to the transflective region ofthe photomask is partially irradiated with the light such that thesecond portion 54 b having a relatively thin thickness is formed. In thecase of using a positive photosensitive film, the above case isreversed, however the portion corresponding to the transflective regionof the photomask is still partially irradiated such that the secondportion 54 b of the photosensitive film pattern 54 is formed.

Referring to FIG. 23, the gate layer 129 and the insulating materiallayer 149 are sequentially etched by using the photosensitive filmpattern 54 as the etching mask. For example, the gate layer 150 may beetched through a wet etching method, and the insulating material layer140 may be etched through a dry etching method. Accordingly, a gatepattern 122 and the insulating pattern 141 having the same plane shapemay be formed under the photosensitive film pattern 54. Thesemiconductor material layer 159 that is not covered by thephotosensitive film pattern 54 may be exposed.

Referring to FIG. 24, the exposed semiconductor material layer 159 isremoved by using the gate pattern 122 and the insulating pattern 141 asthe etching mask to form a semiconductor pattern 150. The semiconductorpattern 150 may have the same plane shape as the gate pattern 122 andthe insulating pattern 141.

Referring to FIG. 25, the photosensitive film pattern 54 is entirelyetched through an ashing method using oxygen plasma to remove the secondportion 54 b by reducing the thickness. Accordingly, the first portion54 a with the reduced thickness remains thereby forming a photosensitivefilm pattern 55.

Referring to FIG. 26, the gate pattern 122 and the insulating pattern141 are sequentially etched by using the photosensitive film pattern 55as the etching mask. Accordingly, the semiconductor pattern 150 that isnot covered by the photosensitive film pattern 55 is exposed and a gateelectrode 124 and a gate insulating layer 142 are formed. The exposedsemiconductor pattern 150 is positioned at both sides with respect tothe semiconductor pattern 150 that is covered by the photosensitive filmpattern 55.

Referring to FIG. 27, the semiconductor pattern 150 undergoes areduction treatment to form the source region 153 and the drain region155 having conductivity. The reduction treatment is the same as that ofthe above exemplary embodiments such that the detailed description isomitted.

Also, the semiconductor pattern 150 that is covered by the gateinsulating layer 142 is not reduced thereby forming the channel region154. The gate electrode 124, the source region 153, and the drain region155 form the thin film transistor along with the channel region 154.

Referring to FIG. 28, after removing the photosensitive film pattern 55,the insulating material is coated on the gate electrode 124, the sourceregion 153, the drain region 155, and the buffer layer 120 to form apassivation layer 180 a. The organic insulating material may be coatedon the passivation layer 180 a to additionally form the organic layer180 b.

As shown in FIG. 20, the passivation layer 180 a and the organic layer180 b may be patterned to form the contact holes 183, 185, and 181, andthen the source electrode 173 and the drain electrode 175 may be formedon the organic layer 180 b.

As described above, according to exemplary embodiments of the presentinvention, the gate electrode 124 and the source region 153 or the drainregion 155 of the thin film transistor are almost not overlapped or areslightly overlapped such that the parasitic capacitance between the gateelectrode 124 and the source region 153 or the parasitic capacitancebetween the gate electrode 124 and the drain region 155 may be verysmall. Accordingly, the on-current and the mobility of the thin filmtransistor may be increased and the on/off characteristic of theswitching element of the thin film transistor may be improved. As aconsequence, the RC delay may be decreased in the display device appliedwith this thin film transistor. Accordingly, the manufacturing cost maybe reduced by obtaining a margin when reducing the thickness of thedriving signal wire. Also, the characteristic of the thin filmtransistor itself is excellent such that the size of the thin filmtransistor may be reduced and a margin for forming a minute channel maybe obtained.

According to exemplary embodiments, FIG. 29 is a flowchart of a processfor manufacturing a thin film transistor array panel. In step 201, agate electrode is formed on an insulation substrate. In step 203, a gateinsulating layer is deposited on the gate electrode. A semiconductorpattern is formed on the gate insulating layer. (step 205) In step 207,an etch stopper is formed on the semiconductor pattern on thesemiconductor pattern. In step 209, a source region and a drain regionare formed by treating the portions of the semiconductor pattern thatare exposed by the etch stopper, thereby forming a channel region. Acarrier concentration of the source region and the drain region islarger than a carrier concentration of the channel region.

According to exemplary embodiments, FIG. 30 is a flowchart of a processfor manufacturing a thin film transistor array panel. In step 301, asemiconductor pattern comprising an oxide semiconductor is formed on aninsulation substrate. In step 303, an insulating material is depositedon the semiconductor pattern to form an insulating material layer. Perstep 305, a gate electrode is formed on the insulating material layer.In step 307, the insulating material layer is patterned by using thegate electrode as an etching mask to form a gate insulating layer and toexpose a portion of the semiconductor pattern. In step 309, the exposedsemiconductor pattern is treated to form a channel region covered by thegate electrode, and to form a source region and a drain region facingeach other with respect to the channel region, wherein a carrierconcentration of the source region and the drain region is larger than acarrier concentration of the channel region.

The above processes, when applied in manufacturing processes for makinga display panel capable of providing excellent switching element byimproving current mobility of thin film transistor. In addition, theseprocesses can solve RC delays of the thin film transistor.

While this invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

It will be apparent to those skilled in the art that variousmodifications and variation can be made in the present invention withoutdeparting from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A thin film transistor comprising: a gate linecomprising a gate electrode; a gate insulating layer positioned on orunder the gate line; a channel region overlapping the gate electrode,the gate insulating layer interposed between the channel region and thegate electrode; a source region and a drain region, facing each otherwith respect to the channel region, positioned in the same layer as thechannel region, and connected to the channel region; and a linear etchstopper and an etch stopper connected to the linear etch stopper, theetch stopper covering the channel region, wherein a boundary line of thegate electrode extends substantially parallel to a boundary line of theetch stopper, the channel region, the source region, and the drainregion comprise an oxide semiconductor, a carrier concentration of thesource region and the drain region is larger than a carrierconcentration of the channel region, and the linear etch stopper extendssubstantially parallel to the gate line and overlaps the gate line. 2.The thin film transistor of claim 1, wherein the source region and thedrain region comprise a reduced oxide semiconductor.
 3. The thin filmtransistor of claim 2, wherein the source region and the drain regionfurther comprise at least one of fluorine (F), hydrogen (H), and sulfur(S).
 4. The thin film transistor of claim 3, wherein a concentration ofat least one of fluorine (F), hydrogen (H), and sulfur (S) included inthe source region and the drain region is equal to or more than about10¹⁵ units/cm³.
 5. The thin film transistor of claim 4, wherein thecarrier concentration of the channel region is less than about 10¹⁸units/cm³, and the carrier concentration of the source region and thedrain region is equal to or more than about 10¹⁸ units/cm³.
 6. The thinfilm transistor of claim 5, further comprising a source electrodeconnected to the source region and a drain electrode connected to thedrain region.
 7. The thin film transistor of claim 6, wherein the etchstopper does not substantially overlap the source region and the drainregion.
 8. The thin film transistor of claim 7, wherein an edge boundaryof the etch stopper and an edge boundary of the gate electrode aresubstantially aligned.
 9. The thin film transistor of claim 8, furthercomprising: a passivation layer positioned on the channel region, thesource region, and the drain region; and an upper gate electrodepositioned on the passivation layer and overlapping the channel region.10. The thin film transistor of claim 5, wherein, the gate insulatinglayer and the gate electrode are positioned on the channel region, andan edge boundary of the gate electrode, an edge boundary of the gateinsulating layer, and an edge boundary of the channel region aresubstantially aligned.
 11. The thin film transistor of claim 1, whereinthe source region and the drain region further comprise at least one offluorine (F), hydrogen (H), and sulfur (S).
 12. The thin film transistorof claim 11, wherein a concentration of at least one of fluorine (F),hydrogen (H), and sulfur (S) included in the source region and the drainregion is equal to or more than about 10¹⁵ units/cm³.
 13. The thin filmtransistor of claim 1, wherein the carrier concentration of the channelregion is less than about 10¹⁸ units/cm³, and the carrier concentrationof the source region and the drain region is equal to or more than about10¹⁸ units/cm³.
 14. The thin film transistor of claim 1, furthercomprising an etch stopper covering the channel region, wherein the etchstopper disposed not substantially overlapping the source region and thedrain region.
 15. The thin film transistor of claim 14, wherein an edgeboundary of the etch stopper and an edge boundary of the gate electrodeare substantially aligned.
 16. The thin film transistor of claim 1,further comprising: a passivation layer positioned on the channelregion, the source region, and the drain region, and an upper gateelectrode positioned on the passivation layer and overlapping thechannel region.
 17. The thin film transistor of claim 1, wherein, thegate insulating layer and the gate electrode are positioned on thechannel region, and an edge boundary of the gate electrode, an edgeboundary of the gate insulating layer, and an edge boundary of thechannel region are substantially aligned.